I mean now we're talking semantics. I think one of the ways he's an a-hole is he takes a brusque defensive position about everything [in public] and while he'll give a generic "we have to do everything better including coach better" I don't think I've ever seen him admit to a single specific mistake in the 20 years he's coached.Ok I guess. I mean, I know some guys associated with the Pats - one is a player you'd know very well - and they think he's great. They say his public (press conference/interview) persona is just a thing, and that isn't how he is in real life at all.
But either way, do you think him being an a-hole, as you put it, means he isn't likely to admit to making a mistake? Those seem like very different things.
EDIT: Also that he publicly plays the grouchy curmudgeon and is like Paul Rudd in private doesn't make him not a dick-- it means he's deliberately being kind of nasty to people in some contexts.